Cannot use function as foreach aggregate.

[Lutger]

BCS wrote:
  > I can't help but wonder if this works.
> 
> template ToDelegate(RetType, RetType function(Args) func, Args...)
> {
>     struct S
>     {
>         static S s
>         RetType callMe(Args args)
>         {
>             return func(args);
>         }
>     }
>     alias &S.s.callMe ToDelegate;
> }

Perhaps it could be simplified to this:

ReturnType!(typeof(func)) delegate (A)
toDelegate(alias func, A = ParameterTypeTuple!(typeof(func)) )()
{	
	return ( A args) { return func(args); } ;
}

But it seems there is a bug with type tuples in delegate literals, which 
also affects your example. This can be made to work though with string 
mixins, expanding the tuples to a parameter list.